The present invention relates to automotive external rearview mirror assemblies. More specifically, it relates to the structure and method for installing or removing the mirror glass after all of the other rearview mirror components in a housing unit have been assembled.
Exterior rearview mirrors are used on all types of motor vehicles to provide rearward vision. Typically the mirrors are mounted in an aerodynamic housing which affixes to the outside of the vehicle door panel. The housing supports the mirror glass and also includes other electrical devices, such as, a motorized mirror positioner, heating element for defrosting, and lighting. The mirror assemblies, therefore, include many different components which need to be carefully assembled. For various reasons, the installation of the mirror glass is preferably the final step in the assembly process. Also, because the mirror glass may become broken, it is advantageous to be able to replace the mirror glass without disassembling the rearview mirror housing unit.
In order to provide a convenient means of securing the mirror glass to a supporting element within the rearview mirror assembly, a snap-in type attachment/release means of affixing the mirror glass is desired. However, these attachment methods usually do not meet the requirements of properly holding the mirror glass in place to provide a clear, reflected view. The mirror glass must be held rigidly so that it moves with the vehicle body and is held firmly against rattle or vibration to keep reflected images from being blurred. Prior art snap-fit attachment systems do not reliably meet these attachment requirements. Furthermore, snap-fit attachment systems often can not be used for aesthetic reasons because the mirror glass must fit tightly to the mirror housing around its perimeter and as such the edge gap between the mirror and the housing may be no greater than 5 mm. Aesthetic considerations therefore greatly restrict the possibility of snap-fitting the mirror glass into place by lateral movement.
Various rearview mirror glass snap-in systems have been attempted in the past. For example, U.S. Pat. No. 5,721,646, entitled xe2x80x9cExterior Rearview Mirror For Vehiclexe2x80x9d, discloses a bayonet mounting and latch assembly in which the mirror support panel is attached to the housing supporting structure through an intermediate bezel ring which is rotated to capture headed posts in T-slots formed in the ring. The ring is held at its position of attachment by a resilient latch that snaps into a radial groove on the ring. Vibration is reduced by increasing the natural frequency of the support bracket and housing by increasing the stiffness and rigidity of the support bracket. While this assembly provides a convenient releasable mirror glass element, it is complicated by the use of an intermediate bezel ring and the rigidity of the mirror glass mounting is inherently compromised by the bezel ring engagement tolerance.
There is therefore a need in the art for a snap-in type releasable mirror glass mounting system for an external vehicle rearview mirror assembly which is aesthetically pleasing and which holds the mirror element securely against vibration so that clarity of the reflected vision viewed in the mirror is provided.
In order to meet the need in the art described above, the present system for mounting a mirror element to the housing of a vehicle rearview mirror assembly has been devised. In the present system a releasable snap-in fit of the mirror element to its supporting structure is provided with a minimum of lateral movement required for installation. This necessitates only a very small gap between the edge of the mirror glass and the surrounding housing, thus providing a pleasing appearance. Furthermore, once attached, the mirror is firmly captured by spring force both laterally and axially so that even if the mating elements which releasably engage the parts become worn or are produced with excessive clearance any lost motion is taken up by the spring. The present invention thereby eliminates any rattle of the mirror glass, and therefore improves vision.
The above desirable characteristics of the present invention are provided by a drop-and-slide attachment system in which forward-projecting, notched posts on a support panel fit axially into a slotted, mirror-back mounting plate. When the mirror mounting plate is moved laterally, the posts slide in the slots until the notches engage arcuate edges at one end of each of the slots. During this movement, a stop on the support panel bears against a compression spring on the mounting plate. When the mirror plate reaches the attached home position, a resilient latch snaps behind a retaining abutment of a catch on the support panel trapping the panel against the compressed spring. The spring also forces the support panel axially, as well as laterally, and therefore when the mirror element is locked in place it is captured firmly both laterally and longitudinally because any axial clearance between the notches and posts is also forceably taken up the pressure of the spring.
The latch has a wide engagement tip that bears directly against a broad abutment on the side of the catch. Therefore, the latch also secures the mounting plate to the support panel against rotation. The latch is located on the mounting plate directly behind the perimeter of the mirror glass so that it may be depressed by a tool inserted from the outside along the edge of the glass to release the mounting plate. When the latch is released, the compression spring ejects the mounting plate, moving the notched posts toward their released position. Thus, the mirror glass and mounting plate may be easily removed after assembly and reinstalled.
It is therefore the main object of the present invention to provide a releasable mirror glass mounting system for an external rearview mirror of a vehicle which is aesthetically pleasing and which holds the mirror elements securely against vibration to provide clarity of reflected vision. It is a further object of the present invention to provide a releasable mirror glass mounting system for a rearview mirror in which the mirror glass mounting plate may be secured directly to the motor positioning support panel without the need for additional parts. It is yet another object of the present invention to provide a releasable mirror glass rearview mirror assembly which may be economically produced and which has a long life.
The following drawings and descriptions of the preferred embodiment will further explain in detail the present invention and other objects and advantages will become apparent to those of skill in the art.